feat: add compress middleware

elton.go

@@ -51,8 +51,6 @@ const (
 type (
 	// Skipper check for skip middleware
 	Skipper func(c *Context) bool
-	// Validator validate function for param
-	Validator func(value string) error
 	// RouterInfo router's info
 	RouterInfo struct {
 		Method string `json:"method,omitempty"`
@@ -281,6 +279,7 @@ func (e *Elton) Handle(method, path string, handlerList ...Handler) {
 		index := -1
 		var traceInfos TraceInfos
 		if e.EnableTrace {
+			// TODO 复用tracInfos
 			traceInfos = make(TraceInfos, 0, maxNext)
 		}
 		c.Next = func() error {

middleware/compress.go

@@ -0,0 +1,179 @@
+// MIT License
+
+// Copyright (c) 2020 Tree Xie
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package middleware
+
+import (
+	"bytes"
+	"regexp"
+	"strings"
+
+	"github.com/vicanso/elton"
+)
+
+var (
+	DefaultCompressRegexp = regexp.MustCompile("text|javascript|json")
+)
+
+const (
+	DefaultCompressMinLength = 1024
+)
+
+type (
+	// Compressor compressor interface
+	Compressor interface {
+		// Accept accept check function
+		Accept(c *elton.Context, bodySize int) (acceptable bool, encoding string)
+		// Compress compress function
+		Compress([]byte) (*bytes.Buffer, error)
+		// Pipe pipe function
+		Pipe(*elton.Context) error
+	}
+	// Config compress config
+	CompressConfig struct {
+		// Checker check the data is compressable
+		Checker *regexp.Regexp
+		// Compressors compressor list
+		Compressors []Compressor
+		// Skipper skipper function
+		Skipper elton.Skipper
+	}
+)
+
+// AcceptEncoding check request accept encoding
+func AcceptEncoding(c *elton.Context, encoding string) (bool, string) {
+	acceptEncoding := c.GetRequestHeader(elton.HeaderAcceptEncoding)
+	if strings.Contains(acceptEncoding, encoding) {
+		return true, encoding
+	}
+	return false, ""
+}
+
+// AddCompressor add compressor
+func (conf *CompressConfig) AddCompressor(compressor Compressor) {
+	if conf.Compressors == nil {
+		conf.Compressors = make([]Compressor, 0)
+	}
+	conf.Compressors = append(conf.Compressors, compressor)
+}
+
+// NewCompressConfig create a new compress config
+func NewCompressConfig(compressors ...Compressor) CompressConfig {
+	cfg := CompressConfig{}
+	cfg.AddCompressor(new(GzipCompressor))
+	return cfg
+}
+
+// NewDefaultCompress create a new default compress middleware(include gzip)
+func NewDefaultCompress() elton.Handler {
+	cfg := NewCompressConfig(new(GzipCompressor))
+	return NewCompress(cfg)
+}
+
+// NewCompress create a new compress middleware
+func NewCompress(config CompressConfig) elton.Handler {
+	skipper := config.Skipper
+	if skipper == nil {
+		skipper = elton.DefaultSkipper
+	}
+	checker := config.Checker
+	if checker == nil {
+		checker = DefaultCompressRegexp
+	}
+	compressorList := config.Compressors
+	return func(c *elton.Context) (err error) {
+		if skipper(c) || compressorList == nil {
+			return c.Next()
+		}
+		err = c.Next()
+		if err != nil {
+			return
+		}
+		isReaderBody := c.IsReaderBody()
+		// 如果数据为空，而且body不是reader，直接跳过
+		if c.BodyBuffer == nil && !isReaderBody {
+			return
+		}
+
+		// encoding 不为空，已做处理，无需要压缩
+		if c.GetHeader(elton.HeaderContentEncoding) != "" {
+			return
+		}
+		contentType := c.GetHeader(elton.HeaderContentType)
+		// 数据类型为非可压缩，则返回
+		if !checker.MatchString(contentType) {
+			return
+		}
+
+		var body []byte
+		if c.BodyBuffer != nil {
+			body = c.BodyBuffer.Bytes()
+		}
+		// 对于reader类，无法判断长度，认为长度为-1
+		bodySize := -1
+		if !isReaderBody {
+			// 如果数据长度少于最小压缩长度
+			bodySize = len(body)
+		}
+
+		fillHeader := func(encoding string) {
+			c.SetHeader(elton.HeaderContentEncoding, encoding)
+			c.AddHeader("Vary", "Accept-Encoding")
+			etagValue := c.GetHeader(elton.HeaderETag)
+			// after compress, etag should be weak etag
+			if etagValue != "" && !strings.HasPrefix(etagValue, "W/") {
+				c.SetHeader(elton.HeaderETag, "W/"+etagValue)
+			}
+		}
+
+		for _, compressor := range compressorList {
+			acceptable, encoding := compressor.Accept(c, bodySize)
+			if !acceptable {
+				continue
+			}
+			if isReaderBody {
+				fillHeader(encoding)
+				err = compressor.Pipe(c)
+				// 如果出错直接返回
+				if err != nil {
+					return
+				}
+				// 成功跳出循环
+				// pipe 将数据直接转至原有的Response，因此设置committed为true
+				c.Committed = true
+				// 清除 reader body
+				c.Body = nil
+				break
+			}
+
+			newBuf, e := compressor.Compress(body)
+			// 如果压缩成功，则使用压缩数据
+			// 失败则忽略
+			if e == nil {
+				fillHeader(encoding)
+				c.BodyBuffer = newBuf
+				break
+			}
+		}
+		return
+	}
+}